1. Field of the Invention
This invention concerns vapor seals for storage tanks, in general. More specifically, it relates to a particular combination with a storage tank having a gauge well that is perforated and extends through a floating roof for the tank.
2. Description of the Prior Art
In connection with storage tanks or volatile products, the requirements for eliminating any vapor emissions have been found difficult where the tank has a floating roof and includes a perforated gauge well that extends through the roof with the perforations being applied to reduce venturi effects caused by air movements across the open top of such a well.
The lack of vapor seal caused by the foregoing indicated structure may be overcome by the use of a seal structure according to this invention. Thus, it is an object of this invention to provide for a floating seal arrangement that is applicable to a floating roof tank having a perforated gauge well therein. The floating seal will maintain a substantially vapor tight condition at the gauge well, so long as the seal remains in place during the periods between gauging activities.